Inline stacker with non-interrupt gap generator and integrated drive control and jam response

ABSTRACT

An inline stacker receives a shingled stream of printed sheet products from a printing press, or finishing equipment, at line speed. A sheet counter at an infeed conveyor section controls the operation of the inline stacker. The infeed conveyor can pivot to a divert position where it feeds the stream to a bi-directional conveyor. A following gap generator section of the stacker has two conveyors with opposed movable ends that are physically separated in the conveying direction by a small gap. The infeed conveyor and gap generator conveyor sections carry the stream at a substantially constant speed, which can be the line speed. To produce a gap in the shingled stream that defines a bundle size, the movable conveyor ends defining the gap between the conveyor gap generator sections move downstream in unison at the speed of the upstream conveyor. At the same time, the speed of the downstream conveyor is briefly increased. The movable ends and the increased conveyor speed then return to their initial status. Stacks of a predetermined size are collected on a forked elevator with mirror movement side walls and other product movement and position controls. Ball-screw-driven and cam-driven side joggers (at the infeed) align the stack and infeed stream laterally. The ball screw jogger, under control of a central controller and an associated servo motor rotates continuously in one direction to open the side walls in response to a sensed jam. The stacker is portable and mechanized for side lay adjustment to align with the press or finishing equipment.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under §35 USC 119 of prior U.S.provisional application Ser. No. 60/476,498 filed Jun. 5, 2003, thedisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates in general to apparatus and methods for formingstacks of sheet materials. More specifically, it relates to an in-linestacker that receives a shingled stream of printed sheets, e.g. from aprinting press, and/or in-line or off-line finishing equipment, andreliably forms them into a series of stacks of a predetermined number atpress speed.

In many applications, it is desired to form a shingled stream of sheetproducts into a succession of bundles each containing a known number ofsheet or folded pieces. A major application is the stacking and bundlingof printed material as it leaves a printing press, and/or in-line oroff-line finishing equipment such as rotary cutters, folders,perforators, and die-cutters. Ideally the stacking apparatus is feddirectly from the output of the press or finishing equipment andoperates at the press speed so as not to limit use of the fullproductive capability of the press. Also, the stacking is ideally highlyreliable, which usually means resistant to jams or other interruptionsin the operation of the stacker. Other objectives include the ability tohandle material of varying size, weight and flexibility, to form bundlesof a wide variety of counts, including as few as ten, to reduce bothmake-ready time and the manpower needed to collect and package thematerial, and to control the waste of good printed material.

A large number of stackers are known. U.S. Pat. Nos. 4,130,207 and4,867,435 describe, respectively, a top stacker with an elevator andpusher operating on a shingled stream of booklets, and a belt stackerthat forms a reverse shingled stream of signatures that stack on end ona conveyor. The '207 machine collects a vertical stack of booklets on aset of laterally spaced “finger ramps”. The booklets are aligned byoscillating side plates and an oscillating rear “finger”. The formedstack is pushed from the collection site by a pneumatically driven“finger”.

U.S. Pat. No. 4,161,092 to Buday et al. describes a system that receivesa shingled stream of flat articles, periodically creates a gap in theshingled stream by accelerating a fixed downstream conveyor with respectto a fixed upstream conveyor, and deposits the flat articles in a seriesof moving containers each holding one stack.

U.S. Pat. No. 3,768,382 to Zernov et al. describes an apparatus thatcreates a gap in a shingled stream of carton blanks by momentarilyinterrupting the blanks upstream of a stop point, while increasing theinfeed conveyor speed. The stream of blanks thus gapped collects on anelevator. A pusher plate pushes a completed stack off the elevator ontoa table or conveyor. Retraction of the pusher plate triggers theelevator to lift to a start forming another stack.

U.S. Pat. No. 6,295,922 to Salamone et al. describes another stackeroperating on a shingled stream of goods. A plate or nip roll interruptsthe shingled steam carried on a fixed upstream conveyor while anadjacent, fixed, downstream conveyor carries a downstream set of theshingled goods, thus creating a gap. The shingled, gapped goods are topfed to a collection site on a reciprocating table or elevator. When astack is completed, the elevator table lowers to a point where a pusherremoves the stack from the table to a gripper apparatus that carrieseach stack to a bander or other processing or storage site. Extendiblefingers collect the goods while the elevator table is lowered. The tableis laterally split to allow it to begin to return to a raised,collecting position while the pusher is still extended, or at leastpartially extended. A side jogger aligns the stack by driving stackedgoods against a fixed member.

In known in-line stackers, e.g. those operating with a printing press,there is typically an electrical connection between the press and thestack such as an output signal from an encoder on a rotary cutter thatis used to set the speed of the stacker and control its operation. Inpractice, however, additional wiring at each location is necessary, theencoder signal has proven to be not sufficiently reliable, and thiscontrol is insensitive to downstream problems of the stacker such as apaper jam. Further, jams are facilitated by interruptions in acontinuously moving shingled stream. A “finger” or nip roll that blocksthe advance of the steam causes the lead sheet in the stream toaccumulate and thicken the height of the stream. This “fat” leading endof the stream, once released by lifting the interrupting finger or niproll, is more susceptible to jamming than a stream of uniform height.Jams in known machines are often difficult and time-consuming to clear.Until they are cleared, either the apparatus feeding the product must bestopped, or its output directed to a waste collection or hold system.There is further time and product lost on restart.

SUMMARY OF THE INVENTION

An inline stacker that solves the various problems of prior art stackingsystems noted above can receive a shingled stream of printed sheetproducts from a printing press or finishing equipment at line speed. Asheet counter at an infeed conveyor section controls the operation ofthe inline stacker. The infeed conveyor can pivot to a divert positionwhere it feeds the stream to a bi-directional conveyor. A following gapgenerator section of the stacker has two conveyors with opposed movableends that are physically separated in the conveying direction by a smallgap. The infeed conveyor and gap generator conveyor sections carry thestream at a substantially constant speed, which can be the line speed.To produce a gap in the shingled stream that defines a bundle size, themovable conveyor ends defining the gap between the conveyor gapgenerator sections move downstream in unison at generally at the speedof the upstream conveyor. At the same time, the speed of the downstreamconveyor is briefly increased to a value that is greater than theupstream conveyor speed. Once the gap in the product stream is created,the movable conveyor section ends and the increased conveyor speedreturn to their initial, steady state values.

Stacks of a predetermined size are collected in a “well” on a forkedelevator with mirror movement side walls and other product movement andposition controls. A ball-screw-driven side jogger aligns the stacklaterally. The ball-screw jogger, under control of a central controllerand an associated servo motor rotates continuously in one direction toopen the side walls in response to a sensed jam.

Continuous rotation of the ball screw also changes the lateral dimensionof the collection well to accommodate products of different width. Onepositive control is an idler wheel mounted over the collection well thatdeflects products leaving the gap generator to the collection wellwithout overshoot.

At the infeed, a pair of jogger side walls oscillate laterally in mirrorfashion to align the shingle products in the stream. This oscillation ispreferably cam and spring driven off a rotating shaft. The infeedconveyor is preferably a set of parallel belts, with a wide central beltthat opposes a set of driven nipper wheels and plural narrow beltsspaced to accommodate the oscillating jogger plates at differentsettings for products with different widths.

The stacker is portable and mechanized for side lay adjustment to alignwith the press or finishing equipment.

In one form of the invention an online stacker that receives a stream ofshingled sheet products moving at a first speed and forms the shingledsheet products into a succession of stacks each containing apredetermined number of the sheet products, has 1) an infeed conveyorsection that receives and conveys said the product stream at generallythe first speed, 2) a counter that counts the number of products thusreceived at said infeed section, and generates an output control signalwhen the predetermined number is reached, and 3) a controller for thestacker that coordinates the operation of the online stacker at least inpart in response to the counter output control signals.

In another form, the inline stacker of this invention has a gapgenerator section and a stacker section, the gap generator sectionreceiving said the product stream from the infeed section and conveyingit to the stacker section at generally the first speed with a gap insaid stream between successive adjacent groups of the predeterminednumber of sheet products. In another preferred form of the invention,the gap generator has upstream and downstream conveyor sections withadjacent, movable ends that are 1) physically separated in the directionof movement of the stream, and, 2) can move in unison in the directionof said the product conveying at the speed of the upstream conveyor.While the movable ends move downstream, the speed of the downstreamconveyor section is increased to a second speed in excess of said firstspeed to create the gap in the shingled stream.

In yet another form of the invention, servo motors drive the rolls ofthe infeed, gap generation, and stacker sections as well as theoscillating side walls of the stacking section and a carriage thatcarries the movable, gap-defining end rolls of the two sections of thegap generator. The controller controls the operation of all the servomotors as well as the operation of the diverter and a transfer mechanismfor formed stacks in response to the counter and at least one jamsensor. The diverter and the stack removal can be effected by pneumaticactuators, also controlled by a central controller. The at least one jamsensor is located over the infeed to the stacker section.

These and other features and objects of the invention will be more fullyunderstood from the following detailed description which should be readin light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a stacker constructed according to thepresent invention;

FIG. 2 is a view in side elevation of the stacker shown in FIG. 1;

FIG. 3 is a top plan view of an alternative embodiment of a stackeraccording to the present invention;

FIG. 4 is a view in side elevation of the stacker shown in FIG. 3;

FIG. 5 is a top plan view of the sidelay base of the stacker shown inFIGS. 3 and 4;

FIG. 6 is a detailed view in side elevation of the gap generator sectionand stream diverter of the stacker shown in FIGS. 3 and 4;

FIG. 7 is a top plan detailed view of the output and stack-forming endof the stacker shown in FIGS. 3 and 4;

FIG. 8 is a detailed end view in side elevation of the bucket “paddle”or reciprocating side jogger shown in FIGS. 3, 4, and 8;

FIG. 9 is an end view in side elevation of the stacker shown in FIGS. 3,4, and 7;

FIG. 10 is a view in perspective of the infeed section of the stackershown in FIGS. 3-11 with the diverter in the normal operating positiondirecting product from an upstream press to the stacker;

FIG. 11 is a detailed to plan view of the side jog mechanism at theinfeed of the stacker 10 shown in FIGS. 3, 4, and 9;

FIG. 12 is a perspective view of the infeed section and beginning of thegap generator section looking in the direction of the travel of theshingled stream with the input conveyor lowered to divert the product toa transverse divert conveyor;

FIG. 13 is a view in perspective of the stacker section shown in FIGS.3-11 showing the collection bucket with the elevator lowered and pusherextended;

FIG. 14 is a view in perspective showing the head roll and variableangular position idler rolls;

FIG. 15 is a view in perspective of the stacker shown in FIGS. 3-14showing the ball screw drive with the side jog plates and portions ofthe sidelay assembly; and

FIG. 16 is a view in perspective of the output from the gap generatorsection and the stacking section looking downstream and showing ashingled stream of product carried on conveyor sections.

DESCRIPTION OF THE INVENTION

With reference to FIGS. 1-16, the stacker 10 of the present inventionhas various features that alone, or in combination, solve variousproblems, such as those discussed above, that have plagued the knownstackers. A principal feature is that the control of the stacker speedand stacking operations originates with a sheet counter 12 located at astacker infeed section 14. The counter 12 sets the speed of the stackerto match the output of the equipment 16 which feeds the stacker. For thepurposes of this description, this in-line equipment operating asuccession of flat sheet products to be stacked will be described as aprinting press and the products as printed paper sheets, includingfolder sheets such as signatures. The counter 12 also controls theoperation of a gap generator 18 of the stacker 10 to produce a gap in aninfeed shingled stream 20 of products 22. The gap in the shingled streamis created after a predetermined number of the products has beendetected by the counter 12.

The counter 12 input to a controller 24 generates output control signalsto a set of servo motors M that each drive a conveyor roll 26 and sidejogger plates 28.

The infeed section 14 includes an infeed conveyor 30 that moves betweena run position 30 a that feeds the input shingled stream 20 of products22 for stacking, and a divert position 30 b where the input shingledstream 20 drops to a right angle bump turn assembly 32 operating inconjunction with a divert conveyor 34 oriented generally transverselywith respect to the stacker infeed conveyor 30. The conveyor 30preferably pivots at its upstream end under control of a pneumaticcylinder 36 that is, in turn, actuated by a signal from the controller24. The transverse diverter conveyor is bi-directional. Movement in onedirection carries the diverted, turned shingled stream to a wastecollection bin. Movement in the opposite direction carries “good”product, in a 90°, re-directed shingled stream, to a good productcollection bin for hand bundling or other disposition. Because allproduct input to the stacker—whether stacked, diverted to waste, ordiverted to a good product collection bin—is counted by the counter 12,it is possible to not only reduce waste of good product, but also tokeep count of all dispositions of products received from the press 16and to restart the stacking operation without a loss of count.

The non-diverted input stream 20 is carried on a two-section conveyorbelt 38. The upstream section 38 a carries the shingled stream 20 at afixed input speed set by the counter at a value that accommodates theoutput of the in-line press, finishing, or like equipment 16. The speedcan vary, but for a given product run it remains substantially constant.The downstream section 38 b is driven independently from the upstreamsection by a separate drive roll 26 a and associated servo motor M.There is a slight gap 40 between the output end of the conveyor 38 a onthe input end of the downstream conveyor 38 b. This gap 40 is the pointat which a gap 42 in the shingled stream is created on an output commandsignal from the controller 24 produced when the product cannot reach apreset number equal to the number of products desired in a stack. Thecycle of operation of the stacker 10 is sufficiently fast, e.g. 2seconds or less, that stacks and bundles of as few as ten products canbe formed reliably.

Whereas in the prior art it is known to create a gap by accelerating adownstream conveyor with respect to an upstream conveyor, and whileinterrupting movement the product at a point upstream of the gap betweenthe conveyors, the present invention creates the gap 42 using a moving,conveyor-to-conveyor, gap 40. Movement of the gap 40 is accompanied by abrief acceleration of the conveyor speed of the downstream conveyor 38b, e.g. to a speed faster than the operating speed of the upstreamconveyor 38 a (e.g. twice the press speed), and then a deceleration backto the normal operating speed of conveyor 38 a in coordination with amovement of the conveyor gap 40 back to its steady state startingposition.

To move the gap 40, the conveyor rolls 26 a and 26 b adjacent the gap40, and associated pairs of idle rolls 26 c-26 f are all rotationallymounted on a carriage 44 that reciprocates linearly along the direction46 of the advancing shingled product stream 20. Each conveyor belt iscarried on its end opposite the gap on fixed rollers 26 g, 26 j. As aresult, as the carriage 44 translates in a downstream direction from itsnormal operating position at a speed equal to the incoming materialstream, the upstream conveyor 38 a telescopes out to create a longerupper, product-carrying belt run 38 a, and the downstream conveyor“telescopes” in to shorten the length of the upper downstream belt run38 b′. Because the mutual spacing of the rolls mounted on the carriageare fixed with respect to each other, while the gap 40 moves downstreamat the speed of the upstream conveyor. The increased speed of thedownstream conveyor draws the shingled stream forward at a likeaccelerating speed to create a physical separation or gap 42 in theshingled stream. It is significant that this gap 42 is made without anyphysical interruption or blocking of the movement of the stream 20. Thegap appears with no apparent, or real, slowdown of the flow of products20 along the conveyors 38 a, 38 b. After the shingled gap 42 is created,typically in a fraction of a second, and over a travel of about onefoot, the carriage returns to its starting position as the speed of thedownstream conveyor is decelerated to again match that of the upstreamconveyor. A servo motor M drives the carriage 44 back and forth undercontrol of the controller 24 and in coordination with an increase of thespeed of the downstream conveyor 38 b, and then a return to the normaloperating speed in each shingled gap-creating cycle of operation.

The conveyor belts of the upstream and downstream conveyors 38 a, 38 bare preferably formed as a continuous band or loop of any known suitablematerial. The belts have a width that accommodates all anticipatedproduct widths. At the infeed conveyor, the belt 30 c is not a singleband of material. Rather, there is a narrow central, closed-loop, band30 d, e.g. three inches in width, and at least one, and as shown four,circular cross-section bands 30 e mutually spaced on either side of thewider central band 30 c. A support plate closely underlies the centralband at least at a point coincident with a set of driven trolley niprolls 50 that bear on the shingled stream to control and advance thestream either to the diverter or to the stacker conveyors.

The construction of the infeed conveyor belt 30 c accommodates a pair ofside jogger plates 28, 28 that extend upwardly along the side of theshingled stream and oscillate toward and away from one another, inunison, to repeatedly contact and urge the shingled stream products 22into a laterally aligned stream in a well-defined, central position.

The side jogger plates 28, 28 each have a lower lip 28 aangled inwardlyunder one of the circular cross-section bands 30 c. The position of theside plates is laterally adjustable to accommodate products of varyingwidths. The position of the lips 28 a, 28 a under the bands 30 e assuresthat the products will not jam between the side jogger plates and theconveyor belting. The mirror-image reciprocation of the side plates 28,28 is produced in the preferred form by mounting each plate on a block54 that is axially slideable along a shaft 56 and biased by spring 58toward the shingled stream. A common drive shaft 60 positioned betweenthe mounting shafts carry rotary cams 62, 62 that engage cam followerssecured to the mounting blocks 54. Rotation of the drive shaft therebycauses the side plates to reciprocate in unison, in a mirror-likemanner.

The counter 12 is preferably mounted over the shingled stream at theinfeed section 14. A suitable counter is a Denex brand edge detectorsold under the trade designation “Laser Copy Sensor”. It generates aninfrared beam direction onto the shingled stream and detects the beamreflected off the products 22. Changes in luminance detect product edgesand yield an input product count.

The gapped shingled stream carried in the downstream conveyor exits to acollection well or “bucket” 64 defined by an elevator 66 and back plate69, and at its sides by another set of mirror-image reciprocating joggerplates 68, 68. The elevator 66 preferably has an open frameconstruction. The back plate 69 is positioned to intercept the leadingedge of the products 22 as they exit the conveyor 38 b, causing them totop stack on a pair of rail members 66 b, 66 b extending in thedirection 46 to form the floor of the elevator. The elevator members arelaterally positioned and spaced so that there is a central clearance 66a for a pusher plate 70 when it is extended by pneumatic cylinder 72 topush a completed stack off the elevator to a bander 74, conveyor, or thelike.

The infeed to the collection bucket 64 includes a driven head roll 76and an associated pair of nipping wheels 78, 78 mounted over the driveroll to ensure that the products are driven into the bucket at an angleconducive to building a stack. The angular position of the nippingwheels 78 with respect to the head roll is adjustable to accommodatesheets of different weights, size and flexibility and different travelspeeds. An air jet also assists the stack formation.

The elevator reciprocates vertically under the control of a pair oflaterally spaced air cylinders between a raised, “collect” position anda lowered, stack “discharge” position. In the raised position, the stackis aligned as it is formed by a rear oscillating tapper plate 80 and theside jog plates 68, 68. The side plates are secured to mounting blocks82, 82 that slide axially on a pair of smooth guide shafts 84, 84oriented at right angles to the direction 46. A ball screw arrangementtranslates the jog plates 68, 68 toward and away from one another. Aservo motor M operating under control of the controller 24 rotates ashaft 86 that is threaded half in one direction and half in the otherthe opposite direction. The shaft 86 threads into the blocks 82, 82which act as followers. Rotation of the shaft 86 in one direction, e.g.four revolutions of the associated motor M, translates both plates 68,68 apart, to their original position. A rapid succession of rotations offour revolutions, in alternating directions, produces an oscillation ofthe plates that jogs the products into a laterally aligned stack. Thesame drive mechanism also can set the lateral, non-reciprocatingposition of the plates for different width products. In the event of apaper jam in the bucket, the rotation of the shaft 86 in a directionthat opens the plates 68, 68 quickly and automatically facilitatesclearance of the jam. The plates 68, 68 straddle, and extend below, therails 66 b, 66 b forming the floor of the elevator 66 and the bottom ofthe collection bucket 64. As with the infeed side joggers 28, 28 at theinfeed, this arrangement avoids jamming of the printed sheets betweenthe floor of the elevator and the reciprocating plates.

Lowering of the elevator 66 is controlled by the counter 12 andcontroller 24, not a limit switch, pressure switch, or other mechanical,optical, or electromechanical sensor and/or switch that reacts to theheight of the stack. The formation of a complete stack is determined bythe infeed count. When the desired number of products is collected andaligned in the bucket, the elevator lowers and the pusher 70 isactivated to discharge the completed stack. At the same time, a set offingers 88 are driven forward by associated air cylinders into positionat the upper end of the bucket 64 to continue to receive and collectproducts for the following stacks while the elevator is lowered andcleared. When the empty elevator is raised by its air cylinder 92, 92,it supports the products collected on the fingers 88, which then retractclear of the well. The fingers are spaced to clear the side plates whenextended, and the elevator central clearance 66 a clears the pusher sothat the elevator can start to return to its raised position before thepusher has fully retracted. This construction and mode of operationprovide a cycle time of one to two seconds. With typical press operatingspeeds this allows the formation of stacks containing twenty-fivepieces, or fewer (e.g. ten), sizes not presently obtainable withconventional equipment.

Jam detection and clearance at the bucket 64 are also facilitated by ajam sensor 94 mounted over the collection bucket 64. The sensor can takea variety of forms, but its present preferred form, a bar 96, ispivotally mounted over the bucket 64 with a sensing arm 98 projectingradially toward the well. A spring 100 urges the bar to rotate to aposition that places the free end of the arm 98 in the well, clear ofthe incoming product, but likely to be engaged and moved by anun-stacked accumulation of products in the well associated with a jam orother malfunction. A jam-sensing rotation of the arm and bar, againstthe force of the spring 100, triggers a switch or other sensor,initiating automatic jam-clearance operations. These operations includeoperation of the infeed air cylinders 36, 36 to divert good product tothe divert conveyor 34 which is driven to carry the product to a “goodproduct” collection bin. This stops the input of products until the jamis cleared without wasting those products. As noted above, the ballscrew 88 is operated to fully open the side jog plates and the cylinders94 are actuated to lower the elevator to its discharge position. Theservo motor M driving the conveyor 38 and head roll 76 can also beinstructed to stop or slow. With these operations completed, the jam isreadily and quickly cleared, and an operator can restart the stacker inits normal mode of operation.

More generally, the use of servo motors and an integrated control of allthe servo motors M and air cylinders noted above provide aself-contained, automatic control over the stacker operation, includingjam clearance.

The stacker 10 is supported on a base 102 that has wheels 104 that makeit portable. It can be quickly rolled into position at the end of thepress 16. To stabilize the stacker, actuation of a set of air jacks 106lifts the frame so that the wheels do not support the stacker 10. Finallateral adjustments are then usually necessary to bring the stacker intoadjustment with the output stream from the printer 16. The presentinvention further includes a motorized side-lay adjustment for thislateral alignment. The components described above are secured, directlyor indirectly, to a frame structure 112 organized within a pair ofupright side walls 114 and various support members all in turn supportedon a set of linear bearings 110 that rest on the base 102. The bearingspermit a small movement of the active stacker components with respect tothe frame, e.g. up to three inches, in a direction transverse to thedirection 46. This side-lay adjustment is produced by a motor M-SLmounted on the main stacker that drives a threaded shaft 116 engaged infollower 118 secured, directly or indirectly, to the base 102. Thesefeatures greatly reduce set-up time as compared to known in-linestackers.

When the elevator is lowered to the discharge position and the pusher 70drives the stack from the elevator 66, the stack being dischargedpreferably contacts and drives the preceding stack out of the bander 74where it has been secured with a circumferential band. This arrangementavoids the need for a gripper assembly in the nature of a robotic arm,or the like, to grip and transport the stack from the stacker to adownstream processing, conveyor, or storage site.

The stacker 10 provides a reliable operation with a single steam productinput to the stacker at line speed. Jams are readily cleared and theproduct stream diverted in a way that saves and accounts for goodproducts. The stacker is readily set up, with no electrical or othercontrol connection from the printing press or finishing apparatus to thestacker. The stacker also handles sheet products of varying size,flexibility and weight, and avoids the “fat leading edge” problem thatoccurs with certain known stackers.

While the invention has been described with respect to its preferredembodiments, it will be understood that many modifications andvariations will occur to those skilled in the art. Such modificationsand variations are intended to fall within the scope of the appendedclaims.

1. An inline stacker that receives a stream of shingled sheet productsmoving at a fist speed and forms the shingled sheet products into asuccession of stacks each containing a predetermined number of the sheetproducts, comprising: an infeed conveyor section that receives andconveys said stream at generally the first speed, a counter that countsthe number of products thus received at said infeed section, andgenerates an output control signal when said predetermined number isreached, and a controller for the stacker that coordinates the operationof the online stacker at least in part in response to said counteroutput control signals.
 2. The inline stacker of claim 2 furthercomprising a gap generator section and a stacker section, said gapgenerator section receiving said stream from said infeed section andconveying it to said stacker section at generally the first speed with agap in said stream between successive adjacent groups of thepredetermined number of sheet products.
 3. The inline stacker of claim 2wherein said gap generator has upstream and downstream conveyor sectionswith adjacent, movable ends that are 1) physically separated in thedirection of movement of the stream, and, 2) move in unison in thedirection of said conveying generally at said first speed, while thespeed of said downstream section is increased to a value in excess ofsaid first speed to create said gap in the shingled product stream. 4.The inline stacker of claim 1 or 2 further comprising a diverter thathas a bi-directional conveyor disposed adjacent said infeed sectionthat, upon detection of a jam, receives and transports the stream ofshingled sheet products received at said infeed section before itreaches and is conveyed by said gap generator section.
 5. The inlinestacker of claim 4 wherein said diverter further includes a mechanismfor moving the infeed conveyor between a first position where it feedsthe stream to the gap generator section and a second position where itfeeds the stream to the diverter.